Simulations and symmetries. Issue 4 (28th January 2020)

• Record Type: Journal Article
• Authors: Modi, Chirag; Chen, Shi-Fan; White, Martin
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 492:Issue 4(2020)
• Page Start: 5754
• Page End: 5763
• Publication Date: 2020-01-28
• Subjects: galaxies: haloes -- galaxies: statistics -- cosmological parameters -- cosmology: theory -- large-scale structure of the Universe; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa251
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We investigate the range of applicability of a model for the real-space power spectrum based on N-body dynamics and a (quadratic) Lagrangian bias expansion. This combination uses the highly accurate particle displacements that can be efficiently achieved by modern N-body methods with a symmetries-based bias expansion which describes the clustering of any tracer on large scales. We show that at low redshifts, and for moderately biased tracers, the substitution of N-body-determined dynamics improves over an equivalent model using perturbation theory by more than a factor of two in scale, while at high redshifts and for highly biased tracers the gains are more modest. This hybrid approach lends itself well to emulation. By removing the need to identify haloes and subhaloes, and by not requiring any galaxy-formation-related parameters to be included, the emulation task is significantly simplified at the cost of modelling a more limited range in scale.